Wind and sun powered base station powers up in Africa

Motorola's green alternative

3GSM Motorola is trialling the used of wind and solar powered generators as an alternative to diesel power for remote GSM cell sites.

MTC Namibia will run the alternative power system between April 2007 and July 2007 in what's promoted as the first-ever trial of the technology on a live network. The trial, supported by the GSM Association, involves the installation of the Motorola wind and solar system at an operational MTC Namibia cell site.

The diesel-free power system is been positioned as a green alternative to using fuel generators when a main grid connection is not available or it will take months or years to connect. Motorola says the technology has applications in both the developed and developing world. Western operators might be interested in the technology as a way of reducing their carbon emissions and of reducing operational costs, especially as electricity prices are expected to rise between 30-40 per cent over coming years.

Wind and solar powered stations require less maintenance than a diesel driven generator which generally requires, at a minimum, a monthly visit for refueling. Thomas Quirke, director of marketing at Motorola, said that diesel power is expensive, especially in cases where it needs to be delivered to cell sites without road access, and often gets siphoned off. "Diesel fuel supplies are heavily prone to theft. Thieves will even take diesel generators, given the chance," he said.

The use of alternative power sources makes it potentially more viable for operators to connect people in remote communities with little existing infrastructure or even roads. Motorola has gone for a combined wind and solar powered system (rather than selecting one or the other) because the same rig can be used in a variety of different environments.

Diesel generators remain cheaper to install but this is offset by higher operating expenses. Bio-diesel systems have been trialled by Ericsson as a more enivronmental friendly alternative but this still leaves the problem of refueling that wind and solar-power generation eliminates.

Excess power from wind and solar systems might be either sold to power-generating firms, where connections to a grid are possible, or supplied as a resource to the community around a base station.

The objective of the Namibian trial is to see the effect of factors such as dust on solar panels and the effects of weather. Earlier experiments with the technology suggest that it is physically robust.

Last year, Motorola ran a trial of the technology at its Swindon offices that demonstrated the feasibility of alternative power systems to support remote GSM base stations. "The wind turbine was in operation even after the recent UK storms," Quirke reports.

The UK experimental trial concluded that a combination of solar cells and wind turbines can generate 1,200 watts in a continual cycle; enough to drive a mid-sized cell and support a microwave backhaul installation. Cells might have an operational radius of up to 120km. ®